Method for Controlling as well as Method for Reducing Engine Speed

Abstract

The motion of a piston in an engine is braked, for example, within the scope of a method for controlling the engine speed, in that ignition takes place prior to a predetermined optimum ignition point. In this way, more than half of the fuel burns before the piston reaches top dead center. Thus, before the actual stroke of performing work, the motion of the piston is opposed and the piston and thus the crankshaft are braked.

1 . A method for controlling the speed of an engine which repeatedly passes through a cycle, in which fuel is delivered into the piston chamber and is ignited at the ignition point in the cycle, comprising:
 determining an optimum ignition point in the cycle, the optimum ignition point under predetermined conditions being that ignition point at which ignition of the fuel causes the delivery of maximum output under predetermined conditions by the engine,   detecting the actual engine speed under normal operating conditions; it to   comparing the actual engine speed with a set point engine speed; and   igniting the fuel at the ignition point before the optimum ignition point in at least one cycle if the actual engine speed is greater than the set point engine speed.   
   
   
       2 . The method for controlling engine speed according to  claim 1 , wherein if the actual engine speed is less than or equal to the setpoint engine speed, the fuel is ignited in at least one cycle at the optimum ignition point. 
   
   
       3 . The method for reducing the speed of an engine which repeatedly passes through a cycle, in which the fuel is delivered into the piston chamber of the engine in which a piston moves back and forth, and the fuel is ignited at the instant in the cycle such that the forces which have been applied to the piston during the subsequent ignition process and which brake its motion act overall more strongly than the forces which have been applied to the piston during the combustion process and which accelerate its motion. 
   
   
       4 . The method according to  claim 3 , in which the fuel is ignited early enough in the cycle of back and forth motion of the piston that before reaching the reversal point of the piston more than half the fuel is already burned in the same cycle. 
   
   
       5 . The method according to  claim 1  wherein the method is used in a spark ignition engine.